Surfboard propulsion device



June 7, 1966 c. H. BRAMSON SURFBOARD PROPULSION DEVI CE Filed NOV. 20, 1964 ///I//IIII,

FIG.6.

mvsmox Clive H. Bramson United States Patent O 3,254,622 SURFBOARD PROPULSION DEVICE Clive H. Bramson, 1 Bay St., Oyster Bay, NY. Filed Nov. 20, 1964, Ser. No. 412,639 2 Claims. (Cl. 115-.5)

This invention is a continuation-in-part of my copending with means integral with surfboard-type watercraft adapted to support at least one human being and which means will occasion the motivation of said watercraft when used in the manner described herein.

The primary object of the instant invention resides in the provision of a surfboard-type structure constructed of low density material such as expanded polystyrene, which includes structural means capable of receiving water upon partial or complete submergence thereof in a body of water, said surfboard being motivated as the water is discharged from said means as the latter rises above the surface 'of the body of water by reason of the buoyance of the surfboard.

Another object of the present invention is to provide a flotatable watercraft device, such as the surfboard, with structural means in the form of a cavity or opening therein, wherein the shifting of the weight of the user will occasion selective filling and discharging of water from said structural means to thereby result in motivation of said surfboard.

Another general object of the present invention is to provide a device of the described character which will be simple in structure, economical of manufacture, and highly effective in use.

Other objects and advantages of the instant surfboard amusement device will be set forth in part hereinafter and t in part will be obvious herefrom, or may be learned by practice of the invention, the same being realized and attained by means of the structure defined and pointed out in the appended claims. a

The accompanying drawings referred to herein and constituting a part hereof illustrate embodiments of the invention, and together with the description, serve to explain the principles of the invention.

FIGURE 1 is a side elevational view of a surfboardtype watercraft shown floating upon a body of water with a user standing thereon;

FIGURE 2 is a side elevational View of the device illustrated in FIGURE 1 with the stern portion thereof being submerged by dint of the shifted weight of the user;

FIGURE 3 is a top plan view of the device shown in FIGURES 1 and 2;

FIGURE 4 is a cross-sectional view taken along line 4-4 of FIGURE 3;

FIGURE 5 is a perspective view of a modified form of the surfboard propulsion device; and

FIGURE 6' is an isolated view of the propulsive member removed from the device shown in FIGURE 5.

It will be understood that the foregoing accompanying illustrations are merely exemplary and are for purposes of explanation and are intended to encompass the other configurations regarded as falling within the contemplation of the invention.

Referring now in detail to the preferred embodiment of the invention illustrated in FIGURES 1-4 of the drawings, numeral 1 generally designates the surfboard-type watercraft incorporating the present invention.

Preferentially the material utilized in the construction 2 3,254,622 Patented June 7, 1966 of the device is, as aforesaid, expanded polystyrene, although other suitable materials may be utilized. The density of the materials determine the suitability thereof inasmuch as the operability of the invention is related to the buoyance of the device incorporating the invention. That is, the greater the buoyancy (considered, of course, with other factors, e.g., strength), the greater the propulsion force attainable. The size of the cavity or opening 2, inter alia', is another factor determinative of the propulsive force attainable.

The density range. of the material which has been determined to be most preferable is .8 to 8' pounds per cubic foot and preferably to 15 lbs./ft. expanded polystyrene being readily moldable to within such density ranges. Other materials such as polyurethane and balsa wood, e.g., are available within such a density range and can, therefore, be preferably utilized. Inasmuch as buoyancy, as will be described in greater detail, is critical to the optimum operational character of the device, the foregoing materials can be optimumly employed. However, inasmu-chas any buoyant material of a density less than the density of water, i.e., aproximately 63 lbs./ft. will enable the obtention of some propulsive effect and, therefore, materials having a density less than the density of water although greater than 15 1bs./ft. will also be capable of utilization.

As shown in FIGURE 1 of the drawings, the surfboardlike device 4 includes a bow region 6, a stern region 8,

a central region 7, and upper surface 10 and a lower sur-.

face 12. The stern region 8 is shown to include integrally therewithin aforesaid cavity or opening 2, said cavity being disposed within the raised portion generally designated by numeral 14 and located at the stern region of the device. The raised portion 14 is preferably provided upon the upper surface 10 rather than being made -to depend from the lower surface 12, such being done to avoid frictional resistance to the movement of the device across the surface of the body of water 16. It will be understood, however, that the placement of the cavity, whether it be centrally of the stem or above or below the horizontal plane axis X--X of the surfboard device is a matter of choice and is within the contemplation of the invention.

The cavity 2 opens to the atmosphere at the rear 18 thereof which is at the rear of the surfboard and includes inside wall 20 and closed end 22 as shown. The cavity, when the stern region 8 is submerged partially beneath the water level 24 of the body of water, or completely as shown in FIGURE 2, will fill to some extent or completely with water. Such submergence, as shown in FIG- URE 2 is accomplishable e.g., by the user shifting his weight to the stern region of the surfboard. Upon removing his weight therefrom by moving to the how 6 or central region, the stern region together with cavity 2 integral therewith, will rise to the surface 24 and while doing so will cause the water 26 within the cavity 2 to be discharged therefrom. Assuch discharge occurs the device will be propelled in the direction of arrow 28 which is the direction opposite to the direction of water discharge. Obviously, therefore, it is desirable that the cavity be relatively large to afford a substantial discharge therefrom.

The degree of the propulsiveforce attained is, as aforedescribed, increased as the density of the material is decreased. That is, inasmuch as it is desirable that the volume of water discharged from the cavity 2 be as great as possible, it will therefore be apparent that the higher the device floats upon the water, the greater the portion of 3 and the volumetric capacity of the cavity should be such that a sufiicient quantity of water can be received therewithin whereby the device will be propelled as the water is discharged therefrom.

Referring now to FIGURES 5 and 6 of the drawings,

. 32 by means of wing-nut fasteners 42 which are received through apertures 44 and which extend therethrough for securement to the surfboard. Other suitable fastening means, may, of course, be employed.

The cavity member is preferably fabricated of low density material such as expanded polystyrene or other suitable material or may even be formed of non-buoyant material inasmuch as the buoyancy of the surfboard alone will be sufiicient to raise the stern region 46 to flotation attitude to thus occasion discharge of the water which had entered hollow interior 34 by reason of submergence of said stern region and cavity member as described in connection with the preferred embodiment hereinabove. The manner of attachment of the cavity'member and the position thereof may also be varied, it being appreciated that the direction of movement of the surfboard is opposite to the direction of discharge of the water from the cavity member.

In consonance with the foregoing disclosure it will be further appreciated that small toy models of ships such as submarines, and animals such as ducks and porpoises, may be fabricated of the aforementioned low density materials, a cavity or opening being contained therein in the form of a hollow interior integrally provided, whereby manual partial or complete submergence of the toy in a body of water will result in the cavity or opening being partially or completely filled with water and upon release of the toy the latter will rise to its normally buoyed height on the water, the water being discharged from the cavitybeing capable of causing movement of the toy in the direction opposite to the direction of Water discharging therefrom. Double-jacketed inflatable toys or single skinner inflatable toys having the required cavity or opening are also within the contemplation of the invention. The instant surfboard type watercraft may also be made in various other non-conventional shapes such as round or oval and may be of gas inflatable rubber or plastic material, the average density thereof rendering the device buoyant as, e.g., a rubber raft or tube. It will be further appreciated and understood that shiftable weight means other than a human being may be utilized to accomplish temporary submersion of the surfboard device and cavity. Also, weight means in combination with the human shiftable weight may be used. Weight means and/ or the human being may be slidable, rollably or otherwise shiftably mounted on the board or device to facilitate varying the center of gravity or longitudinal balance of the device. For example, the person may be seated on a slidable seat upon which he can readily and selectively move from the bow region to the stern region and vice versa. Also, as described in the abovementioned parent application, the cavity member can be movably mounted on the surfboard, the primary and essential consideration always being that the cavity or discharge opening thereof be ultimately positioned or positionable so that the water which had entered therein may readily and rapidly be discharged therefrom due to the action or gravity upon the water within the cavity. In this respect it will be obvious that a substantially level or otherwise suitably oriented lower cavity wall will afford ready and rapid discharge from the cavity or opening.

It will be understood that other changes may be made in the form or the invention or mode of operation, which generally stated consists in a device capable of carrying out the objects set forth as disclosed and defined in the appended claims.

What is claimed is:

1. A surfboard-type device capable of supporting at least one human being, said device including a cavity portion having a fill-discharge opening, said fill-discharge opening facing rearwardly of said device, said device being of buoyant character whereby said fill-discharge opening is disposed above the surface of a body of water when said device is in its normally buoyed state, said filldischarge opening being capable of rapidly and readily receiving a volume of water upon submergence thereof beneath the surface of the water upon the application of an external force to said device, said fill-discharge opening being capable of rapidly and readily discharging said volume of water when said external force is removed and said fill-discharge opening rapidly rises to its normally buoyed position above the surf-ace of the water to occasion said rapid discharge of said volume of water therefrom to thereby propel said device in a direction opposite to the direction of the discharging water.

2. The device asset forth in claim 1 wherein said cavity portion is removably attached thereto.

References Cited by the Examiner UNITED STATES PATENTS 2,511,323 6/1950 Briggs et al. 46-95 3,111,695 11/1963 Kelly- 9310 MILTON BUCHLER, Primary Examiner.

ALFRED E. CORRIGAN, Examiner. 

1. A SURFBOARD-TYPE DEVICE CAPABLE OF SUPPORTING AT LEAST ONE HUMAN BEING, SAID DEVICE INCLUDING A CAVITY PORTION HAVING A FILL-DISCHARGE OPENING, SAID FILL-DISCHARGE OPENING FACING REARWARDLY OF SAID DEVICE, SAID DEVICE BEING OF BUOYANT CHARACTER WHEREBY SAID FILL-DISCHARGE OPENING IS DISPOSED ABOVE THE SURFACE OF A BODY OF WATER WHEN SAID DEVICE IS IN ITS NORMALLY BUOYANT STATE, SAID FILLDISCHARGE OPENING BEING CAPABLE OF RAPIDLY AND READILY RECEIVING A VOLUME OF WATER UPON SUBMERGENCE THEREOF BENEATH THE SURFACE OIF THE WATER UPON THE APPLICATION OF AN EXTERNAL FORCE TO SAID DEVICE, SAID FILL-DISCHARGE OPENING BEING CAPABLE OF RAPIDLY AND READILY DISCHARGING SAID VOLUME OF WATER WHEN SAID EXTERNAL FORCE IS REMOVED AND SAID FILL-DISCHARGE OPENING RAPIDLY RISES TO ITS NORMALLY BUOYANT POSITION ABOVE THE SURFACE OF THE WATER TO OCCASION SAID RAPID DISCHARGE OF SAID VOLUME OF WATER THEREFROM TO THEREBY PROPEL SAID DEVICE IN A DIRECTION OPPOSITE TO THE DIRECTION OF THE DISCHARGING WATER. 